I consider self-published novels previously published by major publishers to be fair game, especially when an internet search turns up more information and reviews. A few of these self-pubs once resided in my bookcases.

Do you agree these books are an exception to the self-published rule?

Yes, I don't include backlist as self-pubs. That is really just a format change. I wouldn't post the NEW self-published books of authors who were previously trade published. In other words, the new books they are publishing on their own and have not been trade published, where the presence or quality of editing done is unknown.